Grass-carp definition

A large silvery cyprinid fish (Ctenopharyngodon idella) native to Siberia and China that feeds on vegetation and has been widely introduced to control aquatic weeds.

A large, weed-eating carp (Ctenopharyngodon idella) brought to the U.S. from E Asia to consume the plants in clogged waterways, lakes, etc.; white amur.